Air heater with corrugated core



Nov. 4, 1947. A. JENSEN ET AL.

I AIR HEATER WITH CORRUGATED CORE 3 Sheets-Sheet 1 Filed March l0 1944 IENTORS Imp 4 Hlllllllll NIHIHIIIIII flrl/mr farmer Sven 01m Nov.4, 1947. A. JENSEN ETAL AIR HEATER WITH CORRUGATED CORE 5 Sheets-Sheet 2 Filed March 10, 1944 kw .R mm y INVENTORS .flrifiur Jensen Sven 01m Nov. 4, 1947. JENSEN ET AL. 2,430,227

AIR HEATER WITH CORRUGATED CORE Filed March 10, 1944 5 Sheets-Sheet I5 I INVENTORS flrZ/zur feral/z B, SW11 flu/m Patented Nov. 4, 1947 AIR HEATER WITH CORRUGATED CORE Arthur Jensen and Sven Holm, .Wellsville, N. Y., assignors to The Air Preheater Corporation,

New York, N. Y.

Application March 10, 1944, Serial No. 525,880

2 Claims. 1

The present invention relates particularly to an improved apparatus for preheating air or other fluids by indirect contact with a heating medium such as hot gases of combustion.

The invention is directed to a plate type heat exchange apparatus that is simple in construction and which may readily be assembled or taken apart, as for the cleaning or replacement of elements thereof. The invention will be best understood upon consideration of the following detailed description of illustrative embodiments thereof when read in conjunction with the accompanying drawings in which:

Figure l is a longitudinal sectional view of a unitary furnace and heat exchange apparatus embodyin the present invention;

Figure 2 is a transverse sectional view on the line 2-2 in Figure 1;

Figures 3 and 4 are fragmentary views on an enlarged scale showing modified forms for the heat exchange surface illustrated in Figures 1 and 2;

Figures 5 and 6 are perspective views showing the relationship between major components of the apparatus and illustrating the ease with which access may be had thereto for the purpose of inspecting, cleaning or replacing parts;

Figure 7 is a fragmentary View showing a modified construction for a portion of the apparatus as illustrated in Figure 1.

In the drawings, the numeral lil designates a casing that encloses an annular heat exchange core I l surrounding a central tube l2 which is arranged in Figure 1 to constitute a passage for the heating gases since it communicates at its left hand end with the outlet 13 of a furnace designated as a whole by the numeral I4. The heat exchange core I I is formed with a plurality of fluid passages extending axially of the unit with the passages divided into two groups, alternate passages forming one group and being provided for the flow of heating gas while the air to be heated flows through the intermediate passages that form the other group.

The construction of the heat exchange core II will be readily understood if it is considered that a metallic plate has been formed with very deep folds or corrugations and its ends brought together by wrapping it around the cylindrical tube 1 2 so that the sides [5 of the corrugations (Fig. 2) form two groups of separated passages l6 and H, employed respectively in Figure 1 for the passage of the air to be heated and the heating gas. Bands l 8 hold the unit in annular form. As a result of this construction the passages it are open as by sections 25 of a flange plate 26. Air entering through the inlet 20 of scrollchamber [9 passes in a generally radial direction into the alternate passages l6 adjacent the furnace end thereof and then flows through these passages and axially of the apparatus to an outlet chamber 2! at the end of the heating casing l0 opposite furnace id to be discharged through the air outlet duct 22. The intermediate passages H are closed at their opposite ends or adjacent the air outlet chamber 2! as by plates 21 while at the center of the heat exchange core llopposite the open distal end of tube 12 is a disk 28 closing off communication between the gas side of the apparatus and the air side. The passage-closing plates 21 may be in the form of spoke-like extensions of a central hub or disk 28, all complementary to the flange plate 26 shown in perspective view in Fig. 5. In cases where the furnace Hi is greater in cross section than the tube 12 the outlet end of the furnace is tapered down so that the discharge outlet l3 thereof registers with the open end of the tube 52 that forms the central gas flue of the apparatus as appears in Figs. 1 and 5. The central tube IE or gas flue terminates short of the right hand end of the heat exchange core ll so that the gases flowing from the tube may pass outwardly in radial directions into the passages it along the inner sides 30 thereof which, as may be seen in Figs. 1 and 5 open towards the center of the unit facing the periphery of the tube 12. At their outer sides the passages are closed by the parts 3| of the corrugations while the ends of these passages adjacent the furnace Hi open into a plenum chamber 33 that surrounds the discharge end l3 of the furnace and the inlet end of tube l2 with which it registers, the gases being discharged from chamber 33 through an outlet 34.

As may best be seen in Figures 2 to 4, the socalled corrugations oi the heat transfer core Ii are maintained separated at their bases by spacer pins or bars 23 projecting radially from the centrally located tube I2. Figure 3 shows undulations in portions of the plate from which the Figure 4 a similar effect is obtained by mounting undulated plates 31 in the passages l6, these plates being provided with transversely disposed spacers 38 projecting at the sides thereof to contact the side Walls of the passages 16. Fig. 4 also shows twisted bars extending from the spacers 23 into the passages I! so as to cause a turbulent flow of the gases in their movement through these passages.

In operation, fuel supplied through burners generally designated by the numeral and air admitted through an air tube 36 extending centrally into furnace chamber i4 provide a supply of hot gases of combustion that are discharged from the furnace outlet 13 directly into the central tu-be I2 of the unit. Flowing to the opposite end of the tube I2 the gases pass radially outward into the group of passages I! and reverse their direction to flow through these passages to the plenum chamber 33 and are finally discharged from the outlet 3:3. The air to be heated by means of these gases flows into the inletZiiA of the scroll chamber 28- and passing in a radially inward direction enters the group of passages |6 near the furnace end thereof and moving counterfiow to the streams of heating gases pass axially along the passages lfito the air outlet chamber 2|.

As appears'in' Figures 5 and 6 the entire furnace M of the unit and the plenum chamber 33 that surrounds the discharge end of the furnace constitute a complete component which is hinged at 42 to the adjacent end of the housing It so that upon release of fastening dogs 43 it may be swung away to aiiord access to the tube I2 that forms a gas flue and also to the heat exchange core H, both of these also forming component parts of the unit which may be entirely withdrawn from the casing i6 when the furnacehas been swung to one side.

In Figure 7 the air to-be heated enters a scroll chamber 34 at the outer end of furnace M and flows through a plenum chamber 45 surrounding the outer part of the furnace in a direction axial- Iy of the apparatus to enter the outer ends 46 of the passages [6 which are left partly open for this purpose. I With this form the plenum chamber 33 for the spent gases has a discharge conduit 41 that extends outwardly through the plenum chamber 45 where air first enters the apparatus.

With the construction described, the amount of heat transfer surface may be readily adapted to varying requirements. This is so because not only may the length of the heat exchange cores be altered to suit circumstances but even in a unit of determined exterior dimensions a larger or smaller number of passages may be used in spaced relation about a central tube of determined size. The relative heat exchange capacity of the unit may also be varied as by replacing a core having plane surfaces on the passage walls with a core having undulated plates as shown in Figure 3. or by adding fillers 31 and/or agitators 40 as'shown in Figure 4. The latter function not only to create turbulence of the gases but also as fin-like extensions of the surface of the central tube l2 through which the gas fiOWS'.

The construction of the heat exchanger of several component units including housing, heat exchange core, central tube and furnace together with hinging of the latter to the housing enables ready access to the parts for cleaning, repair or replacement with other components having difierent heat transfer capacities.

While illustrative embodiments of the invention have been shown and described in detail, it will be understood that there are many changes and variations that may be made without departing from the invention and therefore it is desired and intended to include all such changes and variations within the scope of the appended claims.

What we claim is:

1. In heating apparatus; a casing; an annular heat exchange core slidably mounted in said casing and formed with two groups of alternately disposed corrugations extending longitudinally of the casing; means closing one end of the passages of one group and which open along the sides at the periphery of said core; means closing the opposite ends of corrugations of the other group which open along the sides facing the longitudinal axis of said core, said casing in surrounding said core forming longitudinal passages with the corrugations that open towards its periphery; means forming chambers at opposite ends of said casing each in communication with the open ends of the passages of a respective one of the two groups; means closing off the central part of said core at one end to preclude communication with the chamber at said end of the casing; a removable tubular conduit disposed centrally within said core to form passages with said other group of corrugations, said-conduit extending from one end of said core to a point. short of its end adjacent said closure for placing said'conduit in communication with said passages; means forming a chamber adjacent one end of said casing extending around said core-and communicating at the periphery of said core with the passages of said one group adjacent the closed ends thereof; a furnace unit lIlOllIltBd at one end of said casing and having an outlet at one end adjacent the casing; means placing the outlet of said furnac in communication with one of said groups of passages; aud a hinged connection between said casing furnace unit whereby the latter may be away from the end of said casing to permit withdrawal of said tubular conduit and/or core therefrom.

2. In heating apparatus; a casing; a heat exchange core fitting in said casing and formed with a central passag along its longitudinal axis and two groups of alternately disposed corrugations extending longitudinally of the casing; means closing alternate corrugations at opposite ends, the corrugations of one group being open along the sides at the periphery of said core and being disposed in alternation with corrugations of the other group which are open along the sides facing the longitudinal axis of said core, said casing in surrounding said core forming longitudinal passages with the corrugations that open towards its periphery; means closing ofi the central part of said core at one end; a tubular conduit disposed within saidv core to form passages with said other group of corrugations, said conduit extending centrally through said core from it opposite end to a point short of said one end for placing said conduit in communication with the passages that face the axis of said core ad- ,iacent their closed ends; a furnace unit mounted at one end of said casing and having an end outlet adjacent the casing; means forming a tubular extension of the outlet of said furnac in registration with the open end of said tubular conduit opposite the closur for said core; means forming a gas outlet chamber communicating with the open ends of the passages of the group that face the axis of said chamber, said chamber surrounding the tubular extension of said furnace and constituting an integral part of the furnace unit; means forming chambers at opposite ends of said casing in communication with the passages that face the periphery of said core at their open ends and at the periphery of said core, respectively; and detachabl means connecting said casing and furnace unit whereby the latter may be moved with said gas outlet chamber away from the end of said casing to permit withdrawal of said tubular conduit and/or core therefrom.

ARTHUR JENSEN.

SVEN HOLM.

' 6 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,288,028 Richardson June 30, 1942 280,455 Cutler July 3, 1883 610,037 Evans Aug. 30, 1898 540,028 Roelker May 28, 1895 2,087,393 Wilson July 20, 1937 574,447 Pettibone et a1 Jan. 5, 1897 FOREIGN PATENTS 15 Number Country Date 7,809 Sweden Feb. 20, 1896 606,018 Germany Nov. 23, 1934 

